Objective To explore the association between weight-adjusted waist index (WWI) and the risk of arterial stiffness as well as the progression of arterial stiffness.

Methods Based on the Kailuan Study, this study initially included 56 452 participants who underwent brachial-ankle pulse wave velocity (baPWV) measurements between January 2010 and November 2024. The WWI was calculated as waist circumference (cm) divided by the square root of body weight (kg). Participants were categorized into 3 groups according to WWI tertiles. Generalized linear models (GLM) were used to assess the association between WWI and baPWV. The baPWV≥1800 cm/s was defined as arterial stiffness, and logistic regression was used to assess the association between WWI and arterial stiffness. Additionally, 30 467 participants who had at least two baPWV measurements were included to analyze the association between WWI and the progression of baPWV. Lastly, 25 755 participants who were free of arterial stiffness at the first baPWV measurement were included to examine the association between WWI and the risk of incident arterial stiffness using a modified Poisson regression.

Results The GLM analysis showed that high WWI was significantly associated with increased baPWV (β = 42.922, 95%CI: 37.161 to 48.683). Logistic regression analysis indicated that, compared with the the first tertile (T1) group, the risks of arterial stiffness in the second (T2) and third tertile (T3) groups were increased by 16.1% (OR = 1.161, 95%CI: 1.080 to 1.247) and 31.2% (OR = 1.312, 95%CI: 1.223 to 1.407), respectively. During an average follow-up of 5.27 years, the progression of baPWV in the T3 group was 8.568 cm/s higher than in the T1 group (β = 8.568, 95%CI: 1.572 to 15.564). Of the participants without arterial stiffness at baseline, 4 393 developed arterial stiffness during a median follow-up of 4.75 years (interquartile range: 2.57 to 6.96 years). After adjusting for confounding factors, modified Poisson regression analysis showed that compared with the T1 group, the risks of incident arterial stiffness increased by 11.8% in the T2 group (RR = 1.118, 95%CI: 1.043 to 1.198) and by 14.4% in the T3 group (RR = 1.144, 95%CI: 1.071 to 1.224). Furthermore, these associations remained statistically significant after further adjustment for body mass index (BMI) and waist circumference.

Conclusion Higher WWI is positively associated with an increased risk of arterial stiffness and greater progression of arterial stiffness, independent of BMI and waist circumference.